Improvement in planing-machines



J. B. D. LEAVITT.

MPETERS. PHOT0-LTHOGRAPHE, WASHINGTON. 11C- A' UNITED STATES PATENT. OEEIcE JOHN E.. D. LEAvITT, OE LEBANON, NEW HAMPSHIRE.

IMPROVEMENT lIN VPLANnve-MAer-luvlas'.

Specification forming part of Letters Patent No. 204,056, dated May 21V, 1878; 4 application filed March 1, 1878.

l part of this specication, and to the letters and figures of reference marked thereon.

This invention has relation to planing-machines; and the object or purpose thereof is to provide a machine of the character named in which the pressure-roller rolls at all times will work perfectly in accomplishing their purpose, and without danger of the mechanism to which the rolls are connected becoming inoperative by continued use.

The rubber springs heretofore used to hold the pressure-rolls down would in time lose their yielding or elastic qualities, caused by a chemical change in the composition, as well ,asby the constant pressure brought to bear upon the rubber, rendering it compact and hard, and therefore destroying its action as a spring. v

There are equal objections tothe coiled or spiral me'tal springs, as it has been found that after being used for a certainv length of time the coils will become set upon each other, resulting in their entire unfitness as a spring, losing their compression and extension qualities. In the manufacture of this class of springs, in winding the coil the steel is so much strained on the one side and upset on the other that there is no certainty of its expanding or contracting under any very great pressure without dan ger of breaking 5 and if left soft enough to render it less liable to'snap or break it will lose a greater part of its elasticity, and the coils, by constant use, would be permanently compressed upon each other, or, in other words, set, renderingthe spring wholly inadequate as an attachment for the pressurerolls of a planing-machine.

This invention, therefore, is designed to overcome, as far as possible, the diiiiculties attending the class of springs above referred to, by the employment of a flat or half-elliptic spring; also,\in constructing the boxes or bearings in inner sides to receive boxes a, in which isA journaled one of the pressure-rolls, C, of a planing-machine.

Passing through holes in the standards B are rods b, the lower ends thereof pressing upon the boxes a. rEhe rods b are kept pressed down upon the boxes a by a flat or half-elliptic spring, D, the outer ends thereof resting upon the upper ends of the rods.

The springs D, if desired, maybe formed of a single piece of at metal, or made in leaves c, and may be connected in any suitable manner to the machine, so that its outer ends will be free to act upon the rods b. In this instance, however, I have shown a side piece or casting, d, with ears or projections e, between which the spring is placed. The lower projection acts as a stop, and the upper one receives a suitable screw, j', for regulating the action of the spring, the same being formed upon its upper surface with a depression to receive the end of the screw.

If found practical, in some machines in place of a half-elliptic a full-elliptic spring may be used; and in place of the spring connected or arranged above to press down upon the roll, the spring may, with equal effect, be placed below to draw down, as in either case the roll with spring will have complete control of the board while being planed on either side or in the center; and the amount of pressure needed upon thel roll may be readily obtained by shortening or lengthening the rods b, they being entirely independent of the spring and boxes, rendering them easily Withdrawn.

By the use or application of a flat or elliptic spring in place of the rubber or coiled spring heretofore used, many advantages result therefrom, both as to strength and durability and perfect and regular action, as the pressure of the spring is equal, or nearly so, through its entire length; and should the spring become broken, any blacksmith can repair it or make a new one with comparatively little expense and trouble, while with the spiral or coiled spring it could not be replaced without sendin g to the manufacturers.

I am aware of the patent of J. J.' Russ, No. 7 5,984, dated March 24, 1868, and I do not therefore wish to be understood as claiming anything shown or described in said patent; but,

Having now fully described my invention, what I do claim and as new, and desire to scf cure by Letters Patent, is-

In a planin g-Inachine, a pressure-roll having its hearings in ladjustable boxes, in combina@ tion with an ellipticor at metal spring, andv y JOHN B. D. LEAVITT.

s `Witnesses:

BYRON T. TILDEN, C. A. DOLE. 

